21706080 has 96 divisors (see below), whose sum is σ = 74608128. Its totient is φ = 5260800.

The previous prime is 21706079. The next prime is 21706081. The reversal of 21706080 is 8060712.

It is an interprime number because it is at equal distance from previous prime (21706079) and next prime (21706081).

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21706080.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21706081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3225 + ... + 7335.

It is an arithmetic number, because the mean of its divisors is an integer number (777168).

Almost surely, 2^21706080 is an apocalyptic number.

21706080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21706080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37304064).

21706080 is an abundant number, since it is smaller than the sum of its proper divisors (52902048).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21706080 is a wasteful number, since it uses less digits than its factorization.

21706080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4140 (or 4132 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21706080 is about 4658.9784287975. The cubic root of 21706080 is about 278.9504928794.

Adding to 21706080 its reverse (8060712), we get a palindrome (29766792).

The spelling of 21706080 in words is "twenty-one million, seven hundred six thousand, eighty".